TL, the things happen when you expect them least. You exH went through D so fast, that he didn’t have time to feel much. I think now it is finally hitting him, what he did. He is used to have you in his life. After so many years together I think he still has a lot of emotional attachment to you. He probably just started to realize this.
I will not be surprised that he will continue to text you and even invite you for coffee or something. I would not have any expectations though. You are doing great. Let him believe that you are moving on with your life.
M:50 H:52 S28 (my S from previous marriage) M:17 + 3 BD: 06/12 S: 06/12 - H works in another state